Return of period already?!

My daughter was born via c section 5 weeks ago today. She is EBF- I primarily pump (5-6x/day) but I also nurse her occasionally. I was just greeted by what appears to be my period. I'd also had cramps for the past few days as well as a dip in my breast milk supply. Everything I've read leans toward it being way early for the return of my period but the symptoms line up. Thoughts?? I should note that my post delivery bleeding was basically non existent, so what I have going on now is heavier than what I've experienced since the day she was born.